1. Field of the Invention
The present invention relates to a liquid discharge head for discharging a liquid, a liquid discharge apparatus for discharging a liquid using the liquid discharge head, and a liquid filling method for filling the liquid discharge head with a liquid.
2. Description of the Related Art
Known inkjet recording heads (hereinafter referred to as recording heads) representing a liquid discharge head for discharging a liquid include a recording head having two flow paths enabling ink circulation between a recording head and an ink tank (liquid storage chamber), as discussed in Japanese Patent Application Laid-Open No. 2008-087373. A recording head illustrated in FIG. 4 discussed in Japanese Patent Application Laid-Open No. 2008-087373 includes a filter (215) arranged in a flow path for supplying ink to a discharge port for discharging ink, and a filter (216) arranged in a flow path for guiding ink, which has not been discharged, into an ink tank. The filter (215) arranged in the flow path for supplying ink has a larger area than the filter (216) to reduce a pressure loss by the filter (215), reduce a possibility that ink is not supplied, i.e., defective ink supply occurs, and maintain an ink supply characteristic.
The recording head discussed in Japanese Patent Application Laid-Open No. 2008-087373 is formed by joining a discharge element (150) (liquid discharge member) having a discharge port provided thereon and an ink storage case (210) (liquid supply member) having a filter provided therein.
In a liquid discharge head formed by joining a liquid discharge member and a liquid supply member including a flow path and a filter, when the liquid expansion coefficient of the liquid discharge member and the linear expansion coefficient of the liquid supply member differ from each other, the difference generates a stress in a joined portion between both the joined members. The joined portion may be deformed by the stress. The larger the area of the joined portion between both the members, the greater this problem becomes.
Particularly, in a full-line liquid discharge head in which ink discharge ports are arranged in a range corresponding to the width of a recording medium in a direction crossing a direction in which the recording medium is conveyed, the length of the liquid discharge member in a direction in which the ink discharge ports are disposed is large. When the length of the liquid supply member is similar to the length of the liquid discharge member, as in a case of the liquid discharge head discussed in Japanese Patent Application Laid-Open No. 2008-087373, the area of the joined portion between both the members is further increased so that the joined portion may be deformed.